Synthesis and theoretical study of pyrrole formiate derivatives through ring contraction of 1,4-dihydropyridines
作者:Qiangwen Fan、Runzhi Sun、Zhichang Zhao、Hong Yan
DOI:10.1016/j.tet.2018.11.021
日期:2018.12
Pyrrole formiate derivatives were synthesized through ring contraction of corresponding 3-carboxylate-1,4-dihydropyridines (3-CDHPs) mediated by 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO). 2-Carboxylate-3-aryl-1H-pyrroles (2) and 3-carboxylate-4-aryl-1H-pyrroles (3) were obtained under readily accessible reaction conditions. To gain deep insights into this transformation, DFT calculations were carried
通过2,2,6,6-四甲基哌啶-N-氧基(TEMPO)介导的相应的3-羧酸盐-1,4-二氢吡啶(3-CDHPs)的环收缩,合成吡咯甲酸酯衍生物。在容易获得的反应条件下获得了2-羧酸基-3-芳基-1 H-吡咯(2)和3-羧酸基-4-芳基-1 H-吡咯(3)。为了深入了解这种转变,进行了DFT计算以建立合理的反应机理。结果表明,该过程包括氢的释放,与TEMPO的偶联,DHP支架的开环,O的裂解等。TEMPO部分中的N键,吡咯骨架的制备和甲酰基的解离被纳入转化中,这通过副产物的表征和使用LC-MS方法检测关键中间体得到了进一步证实。